Microsoft Signs Carbon Removal Deal with Alt Carbon

Microsoft signs first Asian carbon removal deal with Indian supplier

Microsoft has agreed to buy 36,920 tonnes of carbon dioxide removal from Alt Carbon, an Indian startup using enhanced rock weathering in the Darjeeling region. The three-year agreement marks the first time Microsoft has purchased carbon removal credits from an enhanced rock weathering project in Asia. It also signals growing commercial interest in a carbon removal method that has largely remained at pilot scale until recently.

The deal connects one of the world’s largest technology companies with a relatively new supplier in India’s emerging carbon removal sector. For UK businesses tracking corporate climate strategies and carbon market developments, the arrangement offers a useful reference point. It shows how large organisations are diversifying their carbon portfolios beyond conventional offsetting and into newer removal technologies.

Microsoft has committed to becoming carbon negative by 2030. That target requires the company to remove more carbon from the atmosphere than it emits. To achieve this, Microsoft runs an active procurement programme that sources carbon removal credits from a range of technologies and geographies. Enhanced rock weathering now sits alongside direct air capture, biochar, and other methods in that portfolio.

What enhanced rock weathering involves

Enhanced rock weathering accelerates a natural geological process. Crushed rock is spread on agricultural land, where it reacts with rainwater and absorbs carbon dioxide from the atmosphere. The carbon is then locked away in stable mineral forms or washed into the ocean as dissolved bicarbonate. This process happens naturally over millions of years. Spreading finely ground rock speeds it up.

The method is considered a form of durable carbon removal because the carbon stays out of the atmosphere for long periods, typically hundreds to thousands of years. This durability makes it more attractive to buyers focused on permanent removal rather than temporary storage. However, measuring and verifying the amount of CO2 removed remains technically complex. It requires monitoring soil chemistry, water runoff, and mineralisation rates across large land areas.

Alt Carbon’s Darjeeling Revival Project applies enhanced rock weathering across tea estates in eastern India. The project combines carbon removal with agricultural benefits, as the crushed rock can improve soil health and crop yields. Consequently, the initiative is framed as both a climate solution and a support mechanism for the regional tea industry. Credits from the project will be verified and issued through Isometric, a carbon removal registry and verification platform.

Commercial structure and verification requirements

The agreement spans three years and covers a fixed volume of 36,920 tonnes of carbon dioxide removal. According to industry reporting, Microsoft may have the option to purchase additional volumes if Alt Carbon meets specified delivery and verification milestones. This contingent structure reflects the still-developing nature of enhanced rock weathering as a commercial carbon removal method.

Verification is central to the deal. Isometric will handle measurement, reporting, and credit issuance. The platform specialises in carbon removal projects and applies rigorous standards to quantify the actual tonnes of CO2 removed. For enhanced rock weathering, this involves field monitoring, geochemical modelling, and independent auditing. The credits issued represent verified tonnes of atmospheric carbon removal, not emissions reductions or avoidance.

Therefore, the arrangement differs from traditional carbon offsets. Offsets typically prevent emissions that would otherwise occur, such as preserving forests or funding renewable energy. Carbon removal, by contrast, extracts CO2 that is already in the atmosphere. This distinction matters for organisations like Microsoft that want to address residual emissions they cannot eliminate through operational changes alone.

Why this deal matters for UK businesses

Microsoft’s procurement decisions often influence wider corporate behaviour. When a company of Microsoft’s size commits to a new carbon removal technology, it sends a signal to suppliers, investors, and other buyers. Enhanced rock weathering has struggled to scale commercially because of high costs, complex verification, and limited buyer interest. A deal like this helps to legitimise the method and may encourage other organisations to explore similar purchases.

For UK businesses, particularly those in supply chains linked to large technology firms, the deal highlights several trends. First, corporate carbon removal procurement is expanding beyond established geographies like North America and Europe. Asia is becoming a more prominent source of carbon removal projects. Second, buyers are willing to work with early-stage suppliers if the underlying science is credible and the verification is robust. Third, durable carbon removal is increasingly seen as a necessary complement to emissions reduction, not a substitute for it.

Many UK businesses face pressure to meet net-zero targets, either through regulatory requirements or customer and investor expectations. Some of that pressure comes from public sector procurement rules. Suppliers bidding for government contracts in England must demonstrate how they will reach net zero by 2050, as required under PPN 06/21. Others face scrutiny from corporate buyers who want to decarbonise their supply chains. In both cases, understanding how carbon removal fits into a credible climate strategy is becoming more important.

Enhanced rock weathering may not be suitable for every organisation. The method works best when applied at scale across large land areas, and the cost per tonne of CO2 removed is still high compared to conventional offsets. However, businesses that need to address residual emissions or want to explore emerging removal technologies should be aware of how the market is developing. This deal suggests that verified, durable carbon removal is moving from niche pilot projects toward more structured commercial agreements.

Details UK businesses should note

• Microsoft has committed to removing 36,920 tonnes of CO2 through enhanced rock weathering in India over three years.
• The agreement is Microsoft’s first enhanced rock weathering purchase in Asia and reflects growing interest in durable carbon removal methods.
• Enhanced rock weathering accelerates a natural process by spreading crushed rock on land, where it absorbs atmospheric carbon dioxide over long timescales.
• Credits from the Darjeeling Revival Project will be verified and issued through Isometric, a carbon removal registry that applies rigorous measurement standards.
• The deal includes potential options for additional volumes if Alt Carbon meets delivery and verification milestones.
• Microsoft’s broader carbon strategy aims to achieve carbon negativity by 2030, requiring both emissions reduction and active carbon removal.

How carbon removal is becoming part of corporate climate strategy

Microsoft’s carbon removal programme is one of the most visible examples of how large organisations are supplementing emissions cuts with removal purchases. The company has stated that it cannot eliminate all emissions through operational changes alone, particularly those embedded in its supply chain and the lifecycle of its products. As a result, it needs to remove carbon from the atmosphere to meet its carbon negative target.

This approach is becoming more common among organisations with ambitious climate commitments. Emissions reduction remains the priority, but residual emissions are inevitable for most businesses. Carbon removal offers a way to address those emissions, provided the removal is permanent and verifiable. Enhanced rock weathering, direct air capture, biochar, and ocean-based methods are all being tested at increasing scale.

For UK businesses, the question is whether and when carbon removal should form part of their own climate strategies. The answer depends on several factors. Businesses should first focus on reducing emissions within their own operations and supply chains. Once those reductions are underway, carbon removal can be considered for residual emissions that are difficult or impossible to eliminate. However, the quality of the removal matters. Not all removal methods are equally durable, and not all verification standards are equally rigorous.

Procurement decisions should therefore be informed by an understanding of the technology, the verification process, and the long-term credibility of the supplier. Microsoft’s approach offers a useful model. The company diversifies across multiple removal technologies, prioritises durable methods, and works with verified registries. UK businesses exploring carbon removal for the first time may find it helpful to apply similar principles, even if the volumes and budgets are smaller.

Where to find more information

The UK government provides guidance on carbon offsetting and removal through the Department for Energy Security and Net Zero. Businesses can find information on emissions reporting, net-zero targets, and public procurement requirements at gov.uk. The government’s net zero strategy sets out the policy framework for decarbonisation across the economy.

For businesses supplying to the public sector, the Crown Commercial Service publishes guidance on PPN 06/21 and carbon reduction plans. This guidance explains what is expected from suppliers bidding for central government contracts. In addition, the Environment Agency offers resources on environmental management and emissions monitoring that may be relevant to businesses considering carbon removal projects or technologies.

Further detail on carbon removal technologies, verification standards, and market developments can be found through industry bodies such as IEMA and BSI. These organisations provide training, standards, and professional guidance for businesses working on climate strategy and environmental management. Meanwhile, our net-zero program for carbon reporting compliance supports UK businesses in meeting regulatory requirements and building credible climate strategies.